Bypass de instrumento endodôntico fraturado: relato de caso / Bypass of a fractured endodontic instrument: case report

Introdução: Mesmo com toda evolução tecnológica desses instrumentos, com o desenvolvimento das limas de liga de níquel-titanio (NiTi) e sistemas mecanizados, as fraturas podem ocorrer durante o preparo químico/mecânico. Existem três abordagens mais regulamente aplicadas para solucionar essa intercorrencia: tentativa de remoção do instrumento com ultrassom, tentativa de ultrapassálo (bypass) ou a obturação do segmento. Objetivo: Relatar um caso da técnica de bypass em instrumento fraturado no canal radicular. Descrição do caso: Paciente, sexo feminino, 47 anos, brasileira, sem condições sistêmicas associadas, foi encaminhada à clínica do Curso de Odontologia da UNIFENAS, Divinópolis, Minas Gerais, Brasil, para resolução de fratura de instrumento no canal mésio- vestibular do primeiro molar superior direito (16). Optou-se pelo tratamento pela técnica de bypass, que envolveu as seguintes etapas: anestesia, abertura, utilização de lima C-Pilot #08 para ultrapassar o instrumento fraturado, odontometria, escalonamento regressivo a partir da lima k#20, desinfecção com hipoclorito de sódio 5%, medicação com hidróxido de cálcio por 21 dias, agitação da substância irrigadora e obturação dos canais radiculares. Conclusão: O bypass ao instrumento é uma técnica conservadora, eficaz e uma solução adequada em casos de fratura de limas endodônticas dentro dos canais radiculares. Essa técnica visa preservar o máximo possível da estrutura dental original, evitando procedimentos mais invasivos.(AU)

Introduction: Even with all technological evolution of these instruments, with the development of nickel-titanium alloy (NiTi) files and mechanized systems, fractures can occur during chemical/mechanical preparation. There are three most commonly applie to resolve this complication: attempting to remove the instrument with ultrasound, attempting to bypass it, or obturating the segment. Objective: To report a case of bypass technique in fractured instrument in the root canal. Case description: A 47-year-old female patient from Brazil, with no associated systemic conditions, was referred to the clinic of the Dentistry Course at UNIFENAS, Divinópolis, Minas Gerais, Brazil, for resolution of an instrument fracture in the mesio-vestibular canal of the right upper first molar (16). Treatment was performed using the bypass technique, which involved the following steps: anesthesia, opening, use of a C-Pilot #08 file to bypass the fractured instrument, odontometry, regressive scaling from the k#20 file, disinfection with 5% sodium hypochlorite, medication with calcium hydroxide for 21 days, agitation of the irrigating substance and root canal filling. Conclusion: Instrument bypass is a conservative, effective technique and an adequate solution in cases of endodontic file fracture within root canals. This technique aims to preserve as much of the original tooth structure as possible, avoiding more invasive procedures.(AU)

Endodontic file separation and its management among dentists in Punjab, Pakistan: a cross-sectional study

The study aimed to find the incidence and awareness of endodontic instrument separation and its management among dental house officers, postgraduate trainees, demonstrators, consultants, and general dentists. Methods: This online questionnaire-based cross-sectional study was conducted with the approval of the IRB in private and public dental hospitals and dental clinics in Punjab. The authors developed the survey tool, which comprises 24 closed-ended items regarding demographics, the incidence of file separation, and awareness about its management. The data were analyzed using IBM SPSS version 24. The Chi-Square Test was used to compare percentages of categorical variables. Results: Postgraduate trainees experienced the most instrument separations (43.6%), made the most retrieval attempts (49.2%), and experienced the most secondary errors during retrieval (52.1%) (p<0.001). Around four out of ten respondents always informed the patients (39.6%) and department (41.6%) about errors. Manual files (69.8%), stainless steel files (75.8%), and short files (60.4%) were more frequently separated, and the most frequent cause was older fatigue files (57.7%). Manual files were more frequently broken in public dental institutes (p=0.003). Two-thirds of the file separations (72.5%) occurred during cleaning and shaping in the apical third of molars (65.1%), especially in mesiolingual canal (56.4%). Bypass attempt was the most common in symptomatic teeth (47.7%). Conclusions: Preventive approaches such as limiting file reuse and constructing a glide path can reduce the occurrence of file separation. Operators should be familiar with the number of uses of the instrument before fatigue and should be trained through workshops and refresher courses

Instrumentação reciprocante em canal mésiovestibular de molar superior após fratura de lima endodôntica: relato de caso / Reciprocal instrumentation in the mesiobuccal canal of the upper molar after endodontic file fracture: case report

Objetivo: reportar um caso clínico de ultrapassagem de instrumento endodôntico fraturado em terço médio de canal mésiovestibular de molar superior permanente, utilizando a técnica de instrumentação reciprocante associada à instrumentação convencional manual e ao gel de E.D.T.A. 24%. Relato de caso: paciente do sexo masculino, 24 anos, normossistêmico, compareceu ao consultório odontológico privado com queixa de dor espontânea e encaminhamento para tratamento endodôntico do dente 17. O diagnóstico foi pulpite irreversível sintomática com indicação de tratamento endodôntico primário. A lima principal escolhida foi a Reciproc® R25 M-wire (VDW), que, durante a instrumentação do canal mésiovestibular, sofreu fratura por torção em terço médio, inviabilizando a continuação em direção apical. Considerações finais: a associação da técnica convencional manual das limas Hedströen com a técnica reciprocante de corte reverso da lima Wave One® Gold Primary e o uso do gel de E.D.T.A. 24% permitiram ultrapassagem do fragmento de lima fraturado em terço médio do canal mésiovestibular do dente 17, promovendo selamento hermético, limpeza, modelagem e obturação satisfatórias.(AU)

Objective: to report a clinical case of a fractured endodontic instrument in the middle third of the permanent maxillary molar maxillary canal using the technique instrumentation reciprocation with technique to conventional manual instrumentation and the E.D.T.A. 24% gel. Case report: a 24-yearold normosystemic male patient came to the private dental office complaining of spontaneous pain and referred for endodontic treatment of tooth 17. The diagnosis was irreversible symptomatic pulpitis with indication for primary endodontic treatment. The main file chosen was the Reciproc® R25 M-wire (VDW), which during the instrumentation of the mesiobuccal canal suffered torsional fracture in the middle third, preventing continuity in the apical direction. Final considerations: the association of the conventional manual Hedströen file technique with the reciprocal reverse cutting technique of the Wave One® Gold Primary file and the use of E.D.T.A. 24% gel allowed the fractured file fragment to be overcome in the middle third of the mesiobuccal canal of tooth 17, promoting hermetic sealing, cleaning, modeling and satisfactory filling. (AU)

Cyclic flexural fatigue resistance of NiTi Controlled Memory and Blue Technology instruments after torsional preloading

Abstract Objective The aim of this study was to evaluate the influence of torsional preloading on the cyclic flexural fatigue resistance of thermally treated NiTi instruments. Material and Methods Ten new instruments New Hyflex CM (HF 30.06; Coltene/Whaladent Inc.), Typhoon CM (TYP 30.06; Clinician's Choice Dental Products) and Vortex Blue (VB 30.06; Dentsply Tulsa Dental) were chosen, based on geometry and specific characteristics of the manufacturing process. The new instruments of each system were tested in a bench device to determine their fatigue resistance through mean value of number of cycles to failure (Nf) (Control Group - CG). Another group of 10 new HF, TYP and VB instruments were submitted to 20 cycles of torsional straining between 0° and 180° (Experimental Group - EG) and then submitted to fatigue until rupture under the same conditions of the CG. Tested instruments were examined by scanning electron microscopy (SEM). Data were analyzed using one-way analysis of variance and post hoc Tukey's test (α=.05). Results Higher fatigue resistance was accomplished by HF instruments, followed by VB and TYP (p<0.05). During the torsional preloading, the lowest mean torque value was observed for TYP instruments (p<0.05). The torsional preload caused a significant reduction in the Nf values (p<0.05) of about 20%, 39% and 45% for instruments HF, VB and TYP, respectively. Longitudinal cracks, generated during the torsional preloading, were present in VB files, but were not observed in the CM instruments (HF and TYP). Conclusions In conclusion, the flexural fatigue resistance of thermally treated instruments is diminished after cyclic torsional loading.

The impact of clinical use on the torsional behavior of Reciproc and WaveOne instruments

ABSTRACT Torsional overload is a fracture representative parameter for instruments in single-file techniques. Objective The aim of this study was to assess the influence of clinical use, in vivo, on the torsional behavior of Reciproc and WaveOne instruments considering the possibility that they degraded with use. Material and Methods Diameter at each millimeter, pitch length, and area at 3 mm from the tip were determined for both types of instruments. Twenty-four instruments, size 25, 0.08 taper, of each system were divided into two groups (n=12 each): Control Group (CG), in which new Reciproc (RC) and WaveOne Primary (WO) instruments were tested in torsion until rupture based on ISO 3630-1; and Experimental Group (EG), in which each new instrument was clinically used to clean and shape the root canals of one molar. After clinical use, the instruments were analyzed using optical and scanning electron microscopy and subsequently tested in torsion until fracture. Data were analyzed using one-way analysis of variance at a=.05. Results WO instruments showed significantly higher mean values of cross-sectional area A3 (P=0.000) and smaller pitch lengths than RC instruments with no statistically significant differences in the diameter at D3 (P=0.521). No significant differences in torsional resistance between the RC and WO new instruments (P=0.134) were found. The clinical use resulted in a tendency of reduction in the maximum torque of the analyzed instruments but no statistically significant difference was observed between them (P=0.327). During the preparation of the root canals, two fractured RC instruments and longitudinal and transversal cracks in RC and WO instruments were observed through SEM analysis. Conclusion After clinical use, no statistically significant reduction in the torsional resistance was observed.

Experimental evaluation of cyclic fatigue resistance of four different nickel-titanium instruments after immersion in sodium hypochlorite and/or sterilization

NiTi instruments have a high risk of separation due to torsional or flexural fatigue (cyclic fatigue). Chemomechanical preparation, cleaning procedures, chemical disinfection and sterilization cause the corrosion of endodontic instruments that may weaken the fracture resistance of the instruments. Objective To assess the effects of NaOCl immersion and autoclave sterilization on the cyclic fatigue resistance of ProFile, FlexMaster, Mtwo and TwistedFiles NiTi instruments (tip size 25, 0.06 taper, n=160). Material and Methods The instruments (n=10 for each subgroup) were dynamically immersed in NaOCl; immersed in NaOCl and sterilized in one autoclave cycle; 5 cycles immersed in NaOCl and sterilized in autoclave and not immersed in NaOCl and not sterilized (control group). Dynamic cyclic fatigue resistance was tested. The number of cycles to failure (NCF) were statistically analyzed (P<0.05). Results Kruskall-Wallis test indicated significant differences among the tested instruments in terms of NCF (P=0.000). The mean NCF of Mtwo (556.75) was higher than that of the Twisted File, Flexmaster and ProFile, 483.1, 376.12, 365.25, respectively. NaOCl immersion and autoclave sterilization have no effect on the NCF values of the tested instruments (P>.05). Conclusions Cyclic fatigue resistance of the tested NiTi instruments cannot be adversely affected by NaOCl immersion and autoclave sterilization. Production process (TwistedFiles) or design (Twisted Files, FlexMaster, Mtwo and ProFile) of the instruments can influence their cyclic fatigue resistance. .

Avaliação clínica do sistema ProTaper na instrumentação de canais de dentes posteriores / Clinical evaluation of the ProTaper in root canal preparation of posterior teeth

A fase de modelagem e limpeza na Endodontia constitui tarefa árdua até para os mais experientes profissionais, conseqüência disso, é o alto número de instrumentos destinados a esta etapa com os mais diferentes desenhos e ligas de constituição. No entanto, o aumento da quantidade nem sempre é proporcional à qualidade dos resultados. Sendo o ProTaper o mais recente lançamento da Dentsply®, o objetivo deste trabalho foi avaliar, clinicamente, as vantagens, desvantagens e limitações deste sistema no preparo de canais de dentes posteriores. Foram preparados 11 dentes posteriores, superiores e inferiores totalizando trinta e três canais radiculares. O sistema ProTaper apresentou facilidade na seqüência de uso dos instrumentos, alto poder de alargamento, facilidade no ajuste do cone de guta-percha e não houve casos de dor pós operatória. Um instrumento (F1) fraturou. O sistema não descarta experiência prévia com a instrumentação automatizada

Fratura dos instrumentos endodônticos de NiTi acionados a motor. Fundamentos teóricos e práticos / Fracture of engine-driven NiTi endodontic instruments. Theoretic and practical concepts

Com base na mecânica da fratura e observaçäo clínica de emprego, foi descrito a falha por torçäo e reflexäo observada nos instrumentos endodônticos de NiTi acionados a motor. A fratura por torçäo ocorre quando a ponta do instrumento fica imobilizada no interior do canal radicular. Neste caso, o esforço de carregamento determina uma deformaçäo plástica na lâmina cortante do instrumento. A continuidade do carregamento pode ultrapassar o limite de resistência à fratura do instrumento, provocando sua falha. A fratura por relexäo ocorre quando, na regiäo de reflexäo de um instrumento, säo geradas tensöes que variam, alternadamente, entre a traçäo e compressäo. A repetiçäo cíclica do carregamento, mesmo com tensäo abaixo do limite de escoamento, obtida em ensaio de traçäo ou torçäo, induz à nucleaçäo de trincas que crescem, coalescem e se propagam até a fratura do instrumento

Técnica do erro conhecido: uma variação da técnica de confecção de prótese total / \"Known fault\" technique: a technical modification of complete denture construction

Quando se examinam pacientes portadores de próteses totais, observamos com certa facilidade os defeitos existentes nestes aparelhos. A técnica proposta visa corrigir as falhas detectadas a partir de uma réplica do aparelho em uso. Com a base de prova em resina, é possível complementá-la em cera para permitir que se façam modificações, adequando às condições individuais do paciente e, assim, conseguindo novos aparelhos com os defeitos existentes corrigidos

Prevalência da sensibilidade dolorosa muscular e na ATM em pacientes portadores de prótese parcial removível (PPR): uma avaliaçäo clínica baseada no sistema de classificaçäo de Kennedy / Prevalence of muscle tenderness and temporomandibular joint (TMJ) pain in RPD patients: a clinical evaluation based on Kennedy's classification system o

Sessenta pacientes, homens e mulheres, com idade variando de 25 a 60 anos, todos portadores de Prótese Parcial Removível (PPR), foram avaliados clinicamente, com a finalidade de analisar comparativamente a prevalência de alguns sinais e sintomas de sensibilidade dolorosa miofascial e na articulaçäo temporomandibular (ATM), entre diferentes tipos de arcos parcialmente edentados, com base na sistematizaçäo apresentada por Kennedy. Com essa finalidade, os pacientes, todos sintomáticos, foram divididos em quatro grupos de 15, correspondendo cada um a uma das quatro classes propostas por Kennedy. Procedeu-se à anamnese, ao exame clínico, particularmente dirigido à palpaçäo muscular e da regiäo da ATM, e à análise cuidadosa do trabalho protético. Estabeleceu-se uma metodologia de testes de escores, com a finalidade de mensurar as respostas dos pacientes. Após as comparaçöes estatísticas, concluiu-se que houve variaçöes significativas entre as diferentes classes estudadas, mostrando uma prevalência na severidade dos sinais e sintomas avaliados para os pacientes portadores de Próteses Parciais Removíveis em arcos parcialmente edentados unilaterais (Classe II de Kennedy). Os resultados sugeriram a existência de uma maior dificuldade no planejamento e preparo de boca para a colocaçäo de PPRs em arcos Classe II de Kennedy, aspectos esses que poderiam atuar como fatores responsáveis pelo mecanismo deflagrador (Trigger) das dores miofasciais e da ATM para esses tipos de arco